Summary ? Resource Core B Measures of structure and strength are essential when assessing functional outcomes in animal models related to musculoskeletal biology and medicine. Evaluating these outcomes requires specialized equipment and expertise, which is impractical and inefficient to recreate in multiple labs. In response to this need, we established the Musculoskeletal Structure and Strength Core. This multifaceted resource supports our Research Community in understanding and implementing techniques to evaluate structure and mechanical properties of musculoskeletal tissues (bone, cartilage, disc, muscle, tendon) derived from animal models. We have had a strong impact. Since 2009, we have provided billable services to 94 unique investigators, who have reported structure or strength data in 176 manuscripts which have been cited 3266 times. The need for these services remains high, with 57 current and projected future users. In order to sustain and extend this resource going forward, we propose two Specific Aims. Aim 1 ? Imaging: Maintain protocols and equipment, provide training and technical support, and perform imaging of musculoskeletal structures and tissues from animal models generated by Research Community investigators. Routine techniques include plane radiography, dual-energy X-ray absorptiometry (DXA), and micro-computed tomography (microCT), each available post mortem or in vivo. We have recently developed methods for contrast-enhanced imaging; we will make these available to our users and will continue to develop new approaches for imaging non-mineralized tissues (cartilage, disc, muscle, tendon). We will present regular seminars on imaging and strengthen our partnership with the Center for Cellular Imaging. Aim 2 ? Mechanical Testing: Perform mechanical testing to assess the functional properties of musculoskeletal structures and tissues from animal models generated by Research Community investigators. Standard testing methods include long-bone bending, vertebral compression, tendon and tendon-to-bone tensile testing, and bone microindentation. Newly established methods include passive and active muscle tension testing and notched bending for fracture toughness. We will present seminars and provide training and enrichment to enhance understanding of biomechanics among Center investigators. In summary, Core B will provide critical support to members of our large Research Community to enable cost-effective utilization of methods to quantify morphology and mechanical properties from musculoskeletal tissues (bone, tendon, muscle, cartilage, disc). Through our efforts we will enhance research productivity and rigor, and provide access to state-of-the-art and emerging techniques.